Conventional time domain multiple access (TDMA) satellite communication networks employ multiple radio stations which communicate through an earth satellite repeater by transmitting time-synchronized bursts of radio energy relative to the repeater and which receive a time multiplex composite of bursts containing corresponding modulated information from the repeater. In TDMA operations, multiple ground stations associated with radio signaling nodes transmit bursts of timeconcentrated information signals on a shared carrier frequency spectrum and receive the same information signals after repetition by the satellite repeater on a shifted carrier frequency spectrum. Each ground station is assigned a particular time slot in a continuum of recurrent frames for transmission of its bursts and for the reception of its own bursts and the bursts of other stations. The bursts interleave at the satellite in close time formation without overlapping. Each earth station includes connections to incoming digital lines originating from terrestrial sources. These input lines are respectively connected to digital data ports on a satellite communications controller (SCC) at the station.
Typical prior art call processing operations are disclosed for example which describe a stored program logic system using a common exchange circuit in a telephone central office. The prior art describes a data memory divided into a plurality of areas, a computer assemblage with a program memory, and separate linking circuits connected to respective peripheral telephone units. A common exchange circuit interconnects the data memory, the computer assemblage and the linking circuits to carry out call processing functions. The call processor operation disclosed in this prior art strongly relies upon the computing power of the host processor since, each time a line is addressed, the bits in it are transferred into the host computer. Furthermore, the call processing apparatus described in this prior art can receive and process only one telephone call at a time.
In modern satellite communications controllers, the overall control operation is carried out by a local host processor which must initiate and supervise digital switching operations, storage transfer operations, operating system program instructions, peripheral equipment coordination operations, as well as the call processing operations required in telephone communications connections. This wide variety of functions places great demands upon the local host processor and oftentimes pending calls cannot be connected because the host processor cannot attend to call processing tasks while engaging in higher priority operations initiating and supervising other functions in the satellite communications controller.